1. Field
The present disclosure relates to an organic light emitting diode (OLED) display. More particularly, it relates to an OLED display with application of a thin film encapsulation (TFE) structure.
2. Description of the Related Technology
An organic light emitting diode (OLED) display typically includes a plurality of OLEDs formed of a hole injection electrode, an organic emission layer, and an electron injection electrode. Each OLED can emit light by energy from excitons generated when electrons and holes that are combined drop from an excited state to a ground state, and the OLED display displays an image by using the light.
Accordingly, the OLED display has self-luminance characteristics, and unlike a liquid crystal display (LCD), its thickness and weight can be reduced since a separate light source is not required. Further, because the OLED display has certain desirable characteristics such as low power consumption, high luminance, and high reaction speed, the OLED display may be suitable for use in a mobile electronic device.
The OLED may be deteriorated due to internal and external factors. With the internal factors, the organic emissive layer may be deteriorated under the atmosphere of oxygen if indium tin oxide (ITO) is the electrode material, or under the interfacial reaction between organic layer components of the organic emissive layer. The external factors may include external moisture and oxygen, and ultraviolet rays. In particular, because the external oxygen and moisture can influence the life span of the OLED, it is very important to package the OLED such that it is sealed from the outside in a vacuum tight manner.
A thin film encapsulation (TFE) technique may be introduced in packaging the organic light emitting diode, which is well known to those skilled in the art. With the thin film encapsulation technique, one or more of inorganic and organic layers can be alternately stacked on the OLEDS formed at the display area of the substrate, thereby covering the display area with a TFE layer. For an OLED display with such a TFE layer, a substrate formed with a flexible film can be bent easily, and can be advantageous in forming a slim structure.
However, a typical TFE layer can have a weak edge compared to a center portion, such that external moisture and oxygen can penetrate through the edge of the TFE layer. That is, the external moisture and oxygen may penetrate through a side of an externally exposed organic layer or an interface between an inorganic layer and an organic layer. Accordingly, the OLEDs disposed at the edge of the display area can be deteriorated such that display failures may occur.
The above disclosure is only provided to enhance understanding of the background and does not necessarily reflect prior art that was known to a person of ordinary skill in the art.